Fiber-optic communication is a mechanism for transmitting information from one place to another by sending pulses of light through an optical fiber. The light forms an electromagnetic carrier wave that may be modulated to carry information. Because of advantages over electrical transmission, optical fibers have largely replaced copper wire communications in core networks. Optical fiber is used by many telecommunications companies to transmit telephone signals, Internet communication, and cable television signals. The process of communicating using fiber-optics involves the following basic steps: creating the optical signal using a transmitter, relaying the signal along a fiber, ensuring that the signal does not become too distorted or weak, receiving the optical signal using a receiver, and converting the optical signal into an electrical signal to determine information carried via the optical signal.